[120.03] On the Properties of Two Strong MgII Absorbers Towards Q0454-220

N. Milutinovic, J.C. Charlton (Penn State), C.W. Churchill (NMSU)

We present the physical properties of two strong MgII
systems at z=0.4744 and z=0.4833 toward the quasar
Q0454-220. A HIRES/Keck spectrum, with resolution R=45,000,
covers prominent low ionization features: MgII, FeII, CaII,
and MgI. A HST/STIS spectrum, with R=30,000, covers the CIV
and SiIV doublets. Coverage of the Lyman series lines and
Lyman break region for these systems is provided by a
HST/FOS spectrum, with R=1,300. The z=0.4744 system is a
sub-DLA system, and the z=0.4833 system also produces a full
Lyman limit break. Beginning with Voigt profile fits to the
highest resolution data, we modeled these systems using the
Cloudy photoionization code. The incident radiation is
assumed to be a Haardt and Madau extragalactic background
spectrum due to quasars and star-forming galaxies. We derive
ranges of ionization parameters, number densities, sizes,
temperatures, and metallicities for the absorbing clouds.

This research was supported by NASA under grant NAG5-6399
NNG04GE73G and by NSF under grant AST-04-07138.

The author(s) of this abstract have provided an email address
for comments about the abstract:
milni@astro.psu.edu